42 Tips and Tricks to Write Faster, Better-Optimized JavaScript Code

Optimize your JavaScript code using modern techniques, tips, and tricks

Sort an array of objects by string property value
How to Round to at most 2 decimal places (only if necessary)
How do I loop through or enumerate a JavaScript Object?
What is the difference between event.preventDefault() and return false
How can I check for an empty/undefined/null string in JavaScript?
How to insert an item into an array at a specific index (JavaScript)?
How to Get the current URL with JavaScript?
Checking if a key exists in a JavaScript object?
How to merge two arrays in JavaScript and remove duplicate items?
How to check whether a string contains a substring in JavaScript?
How to replace all occurrences of a string?
How to correctly clone a JavaScript object?
What is the !! (not not) an operator in JavaScript?
How to Loop through an array in JavaScript
How do I copy to the clipboard in JavaScript?
How do I test for an empty JavaScript object?
How do I make the first letter of a string uppercase in JavaScript?
How can I change an element’s class with JavaScript?
Is it possible to apply CSS to half of a character?
How to append something to an array?
How to check if an object is an array?
How to detect an undefined object property?
How can I convert a string to a boolean in JavaScript?
How can I get query string values in JavaScript?
How to get the length of a JavaScript object?
How to reverse a string that contains complicated emojis?
How can I convert a string to an array of objects in JavaScript?
How to detect if the user changes tab in JavaScript?
How to sum a property value from an array of objects?
How to Format JavaScript date?
How to Generate random string/characters in JavaScript?
How to execute API calls after entering 3 characters in the field?
How to rename object keys inside an array?
How do you clear the focus in javascript?
Binary to String in JavaScript
Shift strings Circular left and right in JavaScript
Regular expression to check for IP addresses JavaScript
How to JSON stringify a JavaScript Date and preserve timezone
JavaScript to check if a string is a valid number
Export a JSON Object to a text file
Wrap long template literal line to multiline without creating a new line in the string
How to copy text from a div to clipboard

#javascript #typescript #angular #node #react

top 30 Python Tips and Tricks for Beginners

Welcome to my Blog , In this article, you are going to learn the top 10 python tips and tricks.

1) swap two numbers.

2) Reversing a string in Python.

3) Create a single string from all the elements in list.

4) Chaining Of Comparison Operators.

5) Print The File Path Of Imported Modules.

6) Return Multiple Values From Functions.

7) Find The Most Frequent Value In A List.

8) Check The Memory Usage Of An Object.

…

#python #python hacks tricks #python learning tips #python programming tricks #python tips #python tips and tricks #python tips and tricks advanced #python tips and tricks for beginners #python tips tricks and techniques #python tutorial #tips and tricks in python #tips to learn python #top 30 python tips and tricks for beginners

Giles Goodwin

1603857900

4 Ways You Can Get Rid of Dirty Side Effects for Cleaner Code in JavaScript

According to an analysis, a developer creates 70 bugs per 1000 lines of code on average. As a result, he spends 75% of his time on debugging. So sad!

Bugs are born in many ways. Creating side effects is one of them.

Some people say side effects are evil, some say they’re not.

I’m in the first group. Side effects should be considered evil. And we should aim for side effects free code.

Here are 4ways you can use to achieve the goal.

1. use strict;

Just add use strict; to the beginning of your files. This special string will turn your code validation on and prevent you from using variables without declaring them first.

#functional-programming #javascript-tips #clean-code #coding #javascript-development #javascript

Tyrique Littel

1604008800

Static Code Analysis: What It Is? How to Use It?

Static code analysis refers to the technique of approximating the runtime behavior of a program. In other words, it is the process of predicting the output of a program without actually executing it.

Lately, however, the term “Static Code Analysis” is more commonly used to refer to one of the applications of this technique rather than the technique itself — program comprehension — understanding the program and detecting issues in it (anything from syntax errors to type mismatches, performance hogs likely bugs, security loopholes, etc.). This is the usage we’d be referring to throughout this post.

“The refinement of techniques for the prompt discovery of error serves as well as any other as a hallmark of what we mean by science.”

J. Robert Oppenheimer

Outline

We cover a lot of ground in this post. The aim is to build an understanding of static code analysis and to equip you with the basic theory, and the right tools so that you can write analyzers on your own.

We start our journey with laying down the essential parts of the pipeline which a compiler follows to understand what a piece of code does. We learn where to tap points in this pipeline to plug in our analyzers and extract meaningful information. In the latter half, we get our feet wet, and write four such static analyzers, completely from scratch, in Python.

Note that although the ideas here are discussed in light of Python, static code analyzers across all programming languages are carved out along similar lines. We chose Python because of the availability of an easy to use ast module, and wide adoption of the language itself.

How does it all work?

Before a computer can finally “understand” and execute a piece of code, it goes through a series of complicated transformations:

static analysis workflow

As you can see in the diagram (go ahead, zoom it!), the static analyzers feed on the output of these stages. To be able to better understand the static analysis techniques, let’s look at each of these steps in some more detail:

Scanning

The first thing that a compiler does when trying to understand a piece of code is to break it down into smaller chunks, also known as tokens. Tokens are akin to what words are in a language.

A token might consist of either a single character, like (, or literals (like integers, strings, e.g., 7, Bob, etc.), or reserved keywords of that language (e.g, def in Python). Characters which do not contribute towards the semantics of a program, like trailing whitespace, comments, etc. are often discarded by the scanner.

Python provides the tokenize module in its standard library to let you play around with tokens:

Python

1

import io

2

import tokenize

3

4

code = b"color = input('Enter your favourite color: ')"

5

6

for token in tokenize.tokenize(io.BytesIO(code).readline):

7

    print(token)

Python

1

TokenInfo(type=62 (ENCODING),  string='utf-8')

2

TokenInfo(type=1  (NAME),      string='color')

3

TokenInfo(type=54 (OP),        string='=')

4

TokenInfo(type=1  (NAME),      string='input')

5

TokenInfo(type=54 (OP),        string='(')

6

TokenInfo(type=3  (STRING),    string="'Enter your favourite color: '")

7

TokenInfo(type=54 (OP),        string=')')

8

TokenInfo(type=4  (NEWLINE),   string='')

9

TokenInfo(type=0  (ENDMARKER), string='')

(Note that for the sake of readability, I’ve omitted a few columns from the result above — metadata like starting index, ending index, a copy of the line on which a token occurs, etc.)

#code quality #code review #static analysis #static code analysis #code analysis #static analysis tools #code review tips #static code analyzer #static code analysis tool #static analyzer

Armando Bruen

1593621572

Who Else Wants to Write Clean JavaScript Code?

Your college: “Who’s the author of this code?”

Expectation: “It’s me!” You answer proudly because that code is beautiful like a princess.

Reality: “Nah, it’s not me!” You lie because that code is ugly like a beast.

Now, if you want to make the expectation become the reality, keep reading.

1. Use meaningful Variable Names

Use meaningful names, which you know exactly what it is at first glance.

// Don't
let xyz = validate(‘amyjandrews’);

// Do
let isUsernameValid = validate(‘amyjandrews’);

It makes sense to name a collection type as plural. Thus, don’t forget the s:

// Don't
let number = [3, 5, 2, 1, 6];

// Do
let numbers = [3, 5, 2, 1, 6];

Functions do things. So, a function’s name should be a verb.

// Don't
function usernameValidation(username) {}

// Do
function validateUsername(username) {}

Start with is for boolean type:

let isValidName = validateName(‘amyjandrews’);

Don’t use constants directly because as time pass you will be like, “What the hell is this?” It’d better to name constants before using them:

// Don't
let area = 5 * 5 * 3.14;

// Do
const PI = 3.14;
let area = 5 * 5 * PI;

For callback functions, don’t be lazy to just name parameters as one character like h, j, d (maybe even you, the father of those name, don’t know what they mean). Long story short, if the parameter is a person, pass person; if it’s a book, pass book:

// Don't
let books = [‘Learn JavaScript’, ‘Coding for Beginners’, ‘CSS the Good Parts’];

books.forEach(function(b) {
  // …
});
// Do
let books = [‘Learn JavaScript’, ‘Coding for Beginners’, ‘CSS the Good Parts’];
books.filter(function(book) {
  // …
});

#coding #javascript-tips #programming #javascript #javascript-development

Edison Stark

1608801687